Mobile computing devices allow a user to perform a variety of functions (including various forms of communication and computing) on a portable device that can be used in a wide variety of settings and contexts. For example, some mobile devices are capable of accessing the Internet, executing gaming applications, playing videos and music, as well as providing functionality of a traditional mobile (e.g., cellular) telephone. Some such mobile computing devices can be wearable by a user (e.g., by attachment and/or coupling to the user's body and/or clothing). Because such devices are generally powered by a small rechargeable battery, a persistent challenge in wearable mobile computing device (“wearable computing device”) design is increasing the length of time that the wearable computing device may operate without recharging the battery.
One method for increasing the length of time that a wearable computing device may operate without recharging the battery is to reduce the amount of power consumed by one or more components of the wearable computing device. A significant consumer of power in a typical wearable computing device is a presence-sensitive display (included in and/or operatively coupled to the wearable computing device) that detects user input and displays graphical content. One example of a presence-sensitive display may be a touchscreen that is physically integrated within a smartphone, tablet, wearable, or other computing device. While the presence-sensitive display is powered on, the wearable computing device may receive indications of user input that are detected at the presence-sensitive display and output graphical content for display at the presence-sensitive display. Wearable computing devices may include a physical button that, when depressed by a user, causes the computing device to power on and/or power off the presence-sensitive display. To conserve power, some wearable computing devices may also automatically power off the presence-sensitive display after a defined time duration during which the presence-sensitive display does not detect user input.
While various options may exist to power off the presence-sensitive display—such as a physical power button and time-based automatic power off—fewer options are available to power on a presence-sensitive display. For instance, a user may need to locate and select a physical power button to power on the presence-sensitive display, which requires an additional user input before interacting with the presence-sensitive display. Alternatively, some wearable computing devices may power on the presence-sensitive display in response to a change in motion of the wearable computing device that was previously at rest. However, such techniques may produce false positives that power on the presence-sensitive display when not intended by the user, thereby further exacerbating the amount of battery life consumed by the presence-sensitive display and thus decreasing the overall battery life of the mobile computing device.